"ransley" wrote in message
...
On Aug 15, 2:24 am, "Robert Green" wrote:
I want to truly silence my Hayden central vac. I bought a muffler for it,
but it's not really of much use since I've already vented the exhaust to
the
outside via an unused dryer vent. The facts are that it's a high RPM motor
and it whines and wakes people up when it's in use when someone's
sleeping.
stuff snipped

I would talk to Hayden , I bet they know what is most cost effective
and works. The Sound- frequency, frequencies, you are deadining have a
wave length that some materials absorbe better than others and foam
may not be as effective as something cheaper. An example of why you
only hear bass from cars or homes that are to loud is the wave of the
low frequency can be 3-4 feet long, and carpet stops the real high
frequencies as they can be only 1/4" long. The frequency of the
whine, Hayden or a musician could figure out, then an enclosure needs
to be designed for that area of frequencies. I guess a 1" drywall box
with 6" fiberglass batts open to the motor might be better and cheaper
but i cant hear the vac from here, the fan idea and completely closing
it is risky, you cant rely on the thermal cutoff in their unit for
saftey. Maybe rubber mounting bushings of the vac would do alot as its
probably vibrating the wall.

Good points. Acoustics can be tricky. It's quite possible just wrapping
the motor end of the assembly will reduce noise enough to not wake anyone.
It's fairly quiet, and you can't really hear it if you're not near it except
when the house is very quiet. If I do my own fans, I will monitor the
internal temperature and kill power to the vac via relay if there's an
overheat. An extra thermal shutoff can't hurt much.

Thanks for your input!

--
Bobby G.